Eastport Pram Build #7: Blades…
So, not a lot of noticeable progress yesterday. I hauled all of the parts and the boat out into the parking lot because I was going to create a lot of sawdust. This last week, I had cut out the rest of the parts for the boat. My method is to get as close to the outside of the Sharpie marker line as possible with either the Japanese pull saw, the circular saw or the jigsaw as possible, then laminate the parts as needed (remember, most of my parts are two-plies of 1/4″ glued together), then sweeten them up with the 5″ oscillating palm sander or the 22″ belt sander.
So, one of the most fun parts of building a boat using plywood to build boat parts is that you can use the plywood laminations as a gauge on how to grind your contour lines. The directions call for shaping the daggerboard and rudder into a hydrofoil shape. The leading edge is shaped for 3/4″ and the trailing edge is feathered down across 2″. This is pretty tricky and you have to be careful not to grind the edges too thin. If I was making a set of racing blades for the Laser racers, the trailing edge would be as thin as a butter knife. Since this is just a pram to mess about with, there’s no need to make anything that fragile. I also checked to make sure the daggerboard fits in its case…
Sweet outwale lamination!
One reason why I dragged the boat outside was to sand down the outwales. They’re solid oak covered with thickened epoxy, so it took a while. Using 40 grit, it ground the laminations flush with each other and took it down to raw wood. I also had to remove the table saw marks from the sides. This is from the crappy portable table saw at work. The outwales are now ready for the roundover bit in the router. A seriously scary step since I’m used to routing flat surfaces. The outwales have a compound curve due to the shear line.
Overall view of progress to date…
The other reason to take the boat outside was to sand the transoms flush. This is a scary step because the oak veneer is so this. I actually started to burn through the veneer in a couple of small places where it required more sanding due to epoxy pooling. I used 220 grit and now the transoms are smooth as a spanked baby’s butt. I think I’ll still be able to finish the transoms bright.
One of the other things I did was ease the edges of the transom doublers. Since mine are 1/4″, I can’t use the router on them, so I hand sanded the concave arcs to make them smooth as they will soon be laminated to the interior of the transoms. I also custom trimmed the doublers to fit within the filleted sides of the boat. I’m still confused about the reality of the situation vs. the directions. Every time there’s a disclaimer in the directions about what not to do, I find that it makes sense to do it that way and several other bloggers have done it that way with no mention of ill effects…
So let’s take another look at where we are on this project. The same caveats still apply…
Where we were last episode:
Layout and cutting parts used so far (not all parts) = 20 hours
Laminating parts (transoms, bulkheads and skeg) = 5 hours
Wiring parts together = 5 hours
Fiberglassing bottom & inside = 5 hours
Installing bulkheads, tabs & fillets = 5 hours
What’s happened since:
Cutting out and laminating additional parts = 5 hours
Sanding all parts to final shape = 5 hours
Total: 50 hours
Let’s look at a rough estimate of the cost.
Using the retail pricing on Go2Marine.com and plywood from Home Depot, let’s see what this project should’ve cost:
1/4″ oak plywood 4′ x 8′ sheets: $29 x 6 sheets = $174
System Three wood flour and silica thickeners = $30
Two gallons of System Three epoxy resin and one gallon of Slow hardener = $280
Gloves, mixing sticks, syringes, cups, etc. = $30
6 yards of 6oz fiberglass 60″ wide = $45
This does not count all of the tools that I’ve used so far. Mostly, it was just the pull saw, but the jigsaw and table saw, drill, router, bits, etc. sure come in handy.
That’s about it for this weekend. Today, I order the sail kit from Sailrite! We’ll see if we can turn the rig shop into a sail loft…